Furnace, battery and charging question.

[Hans627]

When traveling in cold weather and spending the night in a Wal-Mart parking lot or rest stop, I know the furnace fan will draw down the battery relatively quickly. Especially if it is very cold.

Thus a few questions: If the AS is plugged into the TV is there a risk of also depleting the battery in the TV?

When traveling will the TV charge the batteries in the AS?

Thanks!

[idroba]

Originally Posted by Hans627

1. Thus a few questions: If the AS is plugged into the TV is there a risk of also depleting the battery in the TV?

2. When traveling will the TV charge the batteries in the AS?

Thanks!

1: depends on the tow vehicle (tug). Most but not all are wired so that there is a direct connection between the tug battery and the trailer, so if the trailer is left plugged into the tug, it will draw on both the trailer and tug batteries. My Jeep (also a chrysler vehicle, like yours is I think) is wired that way.

Some tugs have a relay which breaks the connection between vehicles automatically when the ignition is off. Mine does not.

2: If there is a battery connection as above, your tug should put some charge into your trailer batteries when towing. It is generally not a lot, from 6 amps to 10 or 11 amps max, due to the wire sizes, and distances involved. My Jeep will charge my old Argosy at about 6 amps max, but it will charge my newer FC 20 at about 11 amps max. The wiring in the old Argosy is longer and more tired after 40 years.

[Alumaholic]

... because most trailer connectors establish a direct connection between the tow vehicle battery(ies) and the trailer battery(ies), its a good idea to always disconnect the electrical umbilical whenever you intend to stay hitched up overnight. Otherwise you may not be able to start the tow vehicle in the morning.
Just be sure to put some visible reminder in the cab of your tow vehicle that you are electrically disconnected, otherwise you'll being going down the road without brake-lights, turn-signals, or brakes; and the umbilical will be dragging.

[Gearheart]

Go easy on the furnace. Rely instead on down comforters or good sleeping bags (rated for -20 or colder) In the morning let the furnace and the stove (you ARE making coffee right?) heat the rig up to comfort.

[Alumaholic]

Gearhart nails it. The furnace is best used briefly in the morning to take the chill off. Long-john pajamas and a nice wool blanket eliminate any need for the furnace at night.

[gecko]

All of the earlier advice is excellent.

On our shakedown cruise with the Airstream, we particularly wanted to check out the Airstream solar as we do a fair amount of boon docking. Camping on the "beach" at our usual Southern Sierra summer spring/summer windsurfing spot (about 2500 ft of elevation), we ran the furnace liberally during the night, where outside temperatures moved into the 20's by morning. We woke up to dead batteries, a coating of frost, and a dead TV battery!

After updating our solar system from the Airstream joke to a real one, we have had no trouble at all, but our traveling routine includes always unplugging from the tow vehicle when we set up camp, and then replugging in before we leave in the morning. And yes, it's a great idea to have a visual reminder! The one time we forgot to hook back up was while traveling from Santa Fe to Telluride, Colorado. It was wonderful when we arrived at our destination to realize that we'd been climbing to 10,000 feet, including some seriously steep descents in some places, with no brake lights and no trailer brakes!!!!!! Thank goodness the one-ton Sprinter has overbuilt brakes, and took stopping itself and the 6,980 lb 28 ft Ocean Breeze like a champ--but driving without trailer brakes is a good recipe to see your trailer traveling alongside you and that's never gonna happen again!

With double the battery bank and enough solar panels and proper controller to fully charge us unless it's a heavily overcast day, setting the thermostat on the furnace to 50-55 (my wife is after all a California girl) and using heavy comforter make for a comfortable and no-problem night, cranking the furnace up in the morning when we make coffee. The furnace cycling on and off during the night does not bother us, although it might wake you up. It's only drawing the major power when the fan has cycled on, and this seems to be about 8 amps. So even if you have it on all the time, if you have been using good power management during the day, 10 hours of furnace use would still draw a max of 80 amps, which is not a problem for the 220 amps that's half of our 440 AGM battery bank. As long as there's sun if we're stationary, or if we're going to drive during the day.

If you don't have solar, that's another matter. You might set the furnace at a lower temperature, or only use sleeping bags or flannel pj's and comforter. But that would be too much like camping and not glamping for us! Which is why we have solar :-)

To give you a relative idea of temperature comforts, do you remember back to the "gas crisis" of 1974, or are you too young? That was the year that, in New York, landlords were told to keep their thermostats set to no higher than 55, day and night. And let me tell, you that was pretty cold, especially when it was below freezing outside all the time so you never had a chance to really get warm--we were all wearing lightweight ski parkas indoors. Of course, it was nice that I was often staying with my girlfriend of the time and her three other friendly flight attendant roomies...cuddling is good for the soul!

[WestieHouse]

I habitually check my brake controller (Tekonsha P3) prior to departing camp each day. This assures me that I remembered to connect my 7-pin again and that the settings are correct.

[blkmagikca]

gecko - We boondock in the Sonora & Mojave. Many of our boondocking friends have installed (as we did) a propane space heater - ours is a blueflame. We keep the galley window cracked open as well as opened vents over the stove and in the bathroom, so there is no chance of oxygen depletion.

[gecko]

Nice! But I think the original question is about possible depletion of tow vehicle battery if left connected to trailer through 7-pin! And that certainly us an issue.

You're offering a nice alternative to running the furnace. For us, since we use the battery bank for other things when boondocking, we'd prefer not to add the weight and storage challenge of another appliance.

[gecko]

I've done some more research on your battery-less solution if using a propane space heater. The following blog covers it beautifully and thoroughly, and may be of interest for those spending time in cold climates. RV Heater: How to Install a Vent-Free Propane Heater in an RV

Thanks again for the heater without batteries (most if the time, anyway!) solution.

[gecko]

roadlesstraveled.us/rv-heater is the right url for the blog--didn't paste in place correctly, so hand typed now!

[Len n Jeanne]

The advantage of the furnace in really cold whether is that it also blows hot air under the floor boards where the waste tanks and pipes are.

[paiceman]

Yes the battery in the TV can be depleted if plugged in and the coach batteries are drained. I unplug every night, even if I do not hook up. Coach batteries can be brought back to life if depleted, TV batteries not so much. Charging from TV to coach can be accomplished if wiring is set up from TV as such and the battery disconnect switch is set to on.

[blkmagikca]

gecko - we have the Procom blueflame heater. Bought it through Amazon for about $120. The blueflame is a convection type of heater; cold air enters through a grill at the bottom and hot air exits through a grill at the top. This naturally promotes air circulation, and results in the whole AS getting heat (right to the back of the bedroom in our 32-ft'er. The catalytic and radiant brick heaters simply radiate heat forward, and you can freeze your "noogies" in the back.

[Jukeboxfun]

In April we parked in a Walmart parking lot, it got cold that night, we ran the furnace, in the morning the battery was down to 50%. We were unplugged from the TV. I won't do that again. The furnace simply uses too much power. We will probably buy a generator or a buddy propane heater in the future.

[acstokes]

For us, this is one of the biggest advantages of 600 watts of solar and 2 Lifeline 6v AGM batteries (300 ah.) wired in series. We can run the furnace all night, deplete the batteries by about 20%, and the next morning by about 10 a.m. our batteries are fully recharged. It's not inexpensive to install, but IMHO if you plan to do much WalMart or other boondock camping the trouble-free nature of an adequate solar system is worth the cost.

[BoldAdventure]

Originally Posted by acstokes

For us, this is one of the biggest advantages of 600 watts of solar and 2 Lifeline 6v AGM batteries (300 ah.) wired in series. We can run the furnace all night, deplete the batteries by about 20%, and the next morning by about 10 a.m. our batteries are fully recharged. It's not inexpensive to install, but IMHO if you plan to do much WalMart or other boondock camping the trouble-free nature of an adequate solar system is worth the cost.

Except for when it's been overcast for a week.

Originally Posted by Hans627

When traveling in cold weather and spending the night in a Wal-Mart parking lot or rest stop, I know the furnace fan will draw down the battery relatively quickly. Especially if it is very cold.

Thus a few questions: If the AS is plugged into the TV is there a risk of also depleting the battery in the TV?

When traveling will the TV charge the batteries in the AS?

Thanks!

So normally I always unplug from my truck. Last Sunday we were in Bryce, UT and the temps dropped down into high 20's at night. Forecast called for overcast and scattered showers for the next couple of days. So we decided to pack up and head down to Sedona. We stopped overnight in Page, Arizona and did just this. Left the Airstream hooked up to the truck and we still ended up using the furnace. As far as I can tell, the draw from the furnace during one night is not enough to effect the Tow Vehicle. It started without problems, and we were on our way.